Stacked semiconductor packages, methods of fabricating the same, and/or systems employing the same

ABSTRACT

An apparatus includes a first substrate having a first land and a second substrate having a second land. A first molding compound is disposed between the first substrate and the second substrate. A first semiconductor chip is disposed on the first substrate and in contact with the first molding portion. A first connector contacts the first land and a second connector contacts the second land. The second connector is disposed on the first connector. A volume of the second connector is greater than a volume of the first connector. A surface of the first semiconductor chip is exposed. The first molding compound is in contact with the second connector, and at least a portion of the second connector is surrounded by the first molding compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 15/241,452, filed Aug. 19, 2016, now allowed, which is aContinuation Application of U.S. application Ser. No. 14/693,352, filedApr. 22, 2015, which is a Continuation Application of U.S. applicationSer. No. 13/934,942, filed Jul. 3, 2013, now U.S. Pat. No. 9,042,115issued May 26, 2015, which is a divisional application of U.S.application Ser. No. 12/910,415, filed Oct. 22, 2010, now U.S. Pat. No.8,508,954 issued Aug. 13, 2013, which claims priority to Korean PatentApplications No. 10-2009-0126345 filed on Dec. 17, 2009 and No.10-2010-0052827 filed on Jun. 4, 2010, the entire disclosures of each ofwhich are incorporated herein by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to stacked semiconductor packages, andmore particularly to stacked semiconductor packages and methods offabricating the same.

2. Description of Related Art

Package on Package (PoP) is an integrated circuit packaging technique toallow vertically combining discrete logic and memory ball grid array(BGA) packages. Two or more packages are stacked with an interface toroute signals between them. This allows higher density, for example inthe mobile telephone/PDA market. In the PoP, two or more memory packagescan be stacked on top of each other. Alternatively, a memory package canbe stacked on a logic package. Using the PoP technique, space in themotherboard can be saved.

SUMMARY

Example embodiments relate to stacked semiconductor chip packages,methods of the fabrication the same and/or systems employing the same.

According to an exemplary embodiment, an apparatus comprises a firstsubstrate comprising a first land and a second substrate comprising asecond land, a first molding compound disposed between the firstsubstrate and the second substrate, a first semiconductor chip disposedon the first substrate and in contact with the first molding portion,and a first connector contacting the first land and a second connectorcontacting the second land, the second connector disposed on the firstconnector, wherein a volume of the second connector is greater than avolume of the first connector, a surface of the first semiconductor chipis exposed, and the first molding compound is in contact with the secondconnector, and at least a portion of the second connector is surroundedby the first molding compound.

The first connector can be disposed in the first molding compound.

A portion of the second connector may not be disposed in the firstmolding compound.

The apparatus may further comprise a second semiconductor chip disposedon the second substrate.

The apparatus may further comprise a second molding compound in contactwith the second semiconductor chip.

The first and second substrates may comprise a PCB or a ceramicsubstrate.

The first and second connectors can be configured to transmit power orsignals.

The first semiconductor chip may comprise a logic device, and the secondsemiconductor chip comprises a memory device.

The first connector and the second connector can be solder balls.

The first semiconductor chip may comprise a plurality of vertical TSVstherein.

The apparatus may further comprise a third connector disposed betweenthe first connector and the second connector.

According to an exemplary embodiment, an electronic system comprises acontrol unit, an input unit configured to transmit an electrical signalto the control unit, an output unit configured to receive the electricalsignal from the control unit and to output a processing result of theelectronic system, a storage unit configured to store data to beprocessed or already processed by the control unit, and a communicationunit configured to receive the electrical signal from the control unitand to transmit or to receive the electrical signal to or from anotherelectronic system, wherein at least one of the control unit, the inputunit, the output unit, the storage unit, and the communication unitincludes the apparatus comprising a first substrate comprising a firstland and a second substrate comprising a second land, a first moldingcompound disposed between the first substrate and the second substrate,a first semiconductor chip disposed on the first substrate and incontact with the first molding portion, and a first connector contactingthe first land and a second connector contacting the second land, thesecond connector disposed on the first connector, wherein a volume ofthe second connector is greater than a volume of the first connector, asurface of the first semiconductor chip is exposed, and the firstmolding compound is in contact with the second connector, and at least aportion of the second connector is surrounded by the first moldingcompound.

The control unit may comprise at least one of a central processing unit(CPU), a main control unit (MCU), a semiconductor module.

The input unit may comprise at least one of a keyboard, a keypad, amouse, a touch pad, or an image recognizer.

The output unit may comprise at least one of a monitor, a printer, or abeam emitter.

The storage unit may comprise at least one of a semiconductor memorydevice, a magnetic storage device, and optical storage device, or aserver having a data storage function.

The communication unit may comprise at least one of a wired transceivingdevice, a wireless transceiving device, or an infrared (IR) port.

The electronic system can be at least one of a computer, a networkserver, a networking printer, a scanner, a wireless controller, a mobilecommunication terminal, a switching system, or any electronic devicecapable of programmed operations.

According to an exemplary embodiment, a method may comprise disposing afirst semiconductor chip on a first substrate, disposing a firstconnector on a land of the first substrate, placing a first moldingcompound on the first substrate and in contact with the firstsemiconductor chip and the first connector, exposing a surface of thefirst substrate, and forming an opening through the first moldingcompound to expose a portion of the first connector.

The method may further comprise disposing a second connector and asecond semiconductor chip on a second substrate, and coupling the firstconnector to the second connector.

The second connector can have a larger volume than the first connector.

The method may further comprise placing a second molding compound incontact with the second semiconductor chip and the second connector.

The method may further comprise dipping the second connector into solderflux.

The first and second connectors can be solder balls.

The second connector can have a larger radius than the first connector.

According to an exemplary embodiment, a method comprises disposing afirst semiconductor chip and a first solder ball on a first substrate,placing a molding compound on the first substrate and in contact withthe first semiconductor chip and the first solder ball, forming anopening through the molding compound to expose a portion of the firstconnector, disposing a second semiconductor chip and a second solderball on a second substrate, and coupling the first solder ball to thesecond solder ball, wherein a radius of the first solder ball is greaterthan a radius of the second solder ball.

The method may further comprise exposing a surface of the firstsubstrate.

The second solder ball can have a larger volume than the first solderball.

The method may further comprise placing a second molding compound incontact with the second semiconductor chip and the second solder ball.

The method may further comprise dipping the second solder ball intosolder flux.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention can be understood in moredetail from the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1A is a schematic plan view of a lower semiconductor packageaccording to an embodiment of the inventive concepts;

FIG. 1B is a schematic plan view of a lower semiconductor packageaccording to an embodiment of the inventive concepts;

FIGS. 2A through 2H are schematic longitudinal sectional views of anapparatus according to embodiments of the inventive concepts;

FIGS. 3A and 3B are schematic longitudinal sectional views ofapparatuses including chip connectors according to embodiments of theinventive concepts;

FIG. 4 is schematic longitudinal sectional view of an apparatusaccording to an embodiment of the inventive concepts;

FIGS. 5A through 5D are schematic longitudinal sectional views of chipconnectors and connection structures thereof according to embodiments ofthe inventive concepts;

FIGS. 6A through 6D are schematic longitudinal sectional views of chipconnectors and connection structures thereof according to embodiments ofthe inventive concepts;

FIGS. 7A through 7D are schematic longitudinal sectional views ofvarious inter-package connectors according to embodiments of theinventive concepts;

FIGS. 8A through 8I are schematic diagrams of real shapes of variousconnectors of package stack structures according to the generalinventive concepts;

FIGS. 9A through 9I are schematic diagrams of shapes of variousconnectors and via holes of package stack structures according to thegeneral inventive concepts;

FIGS. 10A through 10F are schematic longitudinal sectional viewsillustrating a process of forming an upper package in a method offabricating a stack structure of semiconductor packages according to thegeneral inventive concepts;

FIGS. 11A through 11L are schematic longitudinal sectional viewsillustrating a method of fabricating a stack structure of semiconductorpackages according to the general inventive concepts;

FIGS. 12A and 12B are schematic diagrams of semiconductor modulesincluding a stack structure of semiconductor packages according to thegeneral inventive concepts; and

FIG. 13 is a schematic diagram of an electronic system including a stackstructure of semiconductor packages according to the general inventiveconcepts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Example embodiments of inventive concepts will be described withreference to accompanying drawings.

Although a few example embodiments of inventive concepts are shown anddescribed, it would be appreciated by those of ordinary skill in the artthat changes may be made in these example embodiments without departingfrom the principles and spirit of example embodiments, the scope ofwhich is defined in the claims and their equivalents.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layers.In contrast, when an element is referred to as being “directly on”another element or layer, there are no intervening elements or layerspresent. Like numbers refer to like elements throughout. As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of example embodiments.

Example embodiments of inventive concepts are described herein withreference to cross-section illustrations that are schematicillustrations of example embodiments (and intermediate structures) ofinventive concepts. As such, variations from the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Thus, example embodiments shouldnot be construed as limited to the particular shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing.

FIG. 1A is a schematic plan view of a lower semiconductor packageaccording to an embodiment of the inventive concepts. In FIG. 1A, alower semiconductor chip is disclosed. FIG. 1B is a schematic plan viewof a lower semiconductor package according to an exemplary embodiment.In FIG. 1B, a lower semiconductor chip is not disclosed.

Referring to FIG. 1A, a lower semiconductor package 105L may include alower package substrate 110L, a lower semiconductor chip 115L disposedon the lower package substrate 110L, and a plurality of inter-packageconnectors 150 disposed around the lower semiconductor chip 115L.Referring to FIG. 1B, the dotted lines indicate a location configured toreceive the lower semiconductor chip 115L. According to an embodiment,the lower semiconductor package 105L may include a plurality of flipchip landing pads 185 disposed between the lower package substrate 110Land the lower semiconductor chip 115L. The flip chip landing pads 185can be surrounded by the plurality of inter-package connectors 150. Theflip chip landing pads 185 may be electrically connected to otherelements such as, for example, through silicon vias (TSVs), throughsilicon via plugs and/or conductive chip bumps.

FIGS. 2A through 2H are schematic longitudinal sectional views of anapparatus according to embodiments of the inventive concepts.

Referring to FIG. 2A, an apparatus 100 a includes a lower semiconductorpackage 105L, an upper semiconductor package 105U, and inter-packageconnectors 150 a configured to electrically connect the lower and uppersemiconductor packages 105L and 105U. The upper semiconductor package105U is stacked on the lower semiconductor package 105L. A portion ofthe inter-package connectors 150 a may be a part of the lowersemiconductor package 105L. Another portion of the inter-packageconnectors 150 a may be a part of the upper semiconductor package 105U.

The lower semiconductor package 105L may include a lower packagesubstrate 110L, a lower semiconductor chip 115L disposed on a topsurface of the lower package substrate 110L, a lower molding compound130L, and conductive solder balls 125 disposed on a bottom surface ofthe lower package substrate 110L. The lower semiconductor package 105Lmay be formed using, for example, a flip-chip technique. The lowerpackage substrate 110L may comprise, for example, a printed circuitboard (PCB) or a ceramic substrate.

The lower semiconductor chip 115L may comprise a logic device, such as amicroprocessor. The lower semiconductor chip 115L may be disposed on onesurface of the lower package substrate 110L. The lower semiconductorchip 115L may be electrically connected to the solder balls 125 throughconductive chip bumps 120. The conductive chip bumps 120 may be disposedon the top surface of the lower semiconductor substrate 110L. That is,the lower semiconductor chip 115L may include a flip-chip connectionstructure having a grid array according to an embodiment of theinventive concepts.

The conductive chip bumps 120 may be interposed between the lowerpackage substrate 110L and the lower semiconductor chip 115L. Theconductive chip bumps 120 may electrically connect the lower packagesubstrate 110L and the lower semiconductor chip 115L. The conductivechip bumps 120 may include a solder material. Thus, the conductive chipbumps 120 may be formed using, for example, a soldering process.

The conductive solder balls 125 are configured to electrically connectthe apparatus 100 a to a module board or a main circuit board.

The lower molding compound 130L covers the conductive chip bumps 120. Anadhesive may be formed around the conductive chip bumps 120. Forexample, the adhesive can be disposed between the lower semiconductorchip 115L and the lower package substrate 110L. The lower moldingcompound 130L surrounds a lateral surface of the lower semiconductorchip 115L. For example, the lower semiconductor chip 115L may be adheredto the top surface of the lower semiconductor package 105L using theadhesive, and the lower molding compound 130L may surround the lateralsurface of the lower semiconductor chip 115L.

In an embodiment, the adhesive may be included in the lower moldingcompound 130L. In an embodiment, the lower molding compound 130L maysurround lateral surfaces of the inter-package connectors 150 a. In anembodiment, a top surface of the lower semiconductor chip 115L may notbe covered with the lower molding compound 130L. In other words, the topsurface of the lower semiconductor chip 115L is exposed. In anembodiment, a top surface of the lower molding compound 130L is coplanarwith the top surface of the lower semiconductor chip 115L. In anembodiment, since a thickness of the lower semiconductor package 105L isreduced, a thickness of the apparatus 100 a is also reduced. Since thetop of the lower semiconductor chip 115L is exposed, heat can bedissipated without being interrupted by the epoxy molding compound(EMC). As such, heat radiation property can be improved. Since the lowersemiconductor package 105L has a better tolerance or resistance againsta high-temperature process as compared to the one covered by the EMC,the lower semiconductor package 105L may have a better tolerance orresistance against warpage or distortion so that the flatness of thelower semiconductor package 105L and the lower semiconductor chip 115Lcan be improved.

Since physical pressure may be directly applied to top surface of thelower semiconductor chip 115L without passing through a moldingmaterial, a grid array technique or a multilayered molding technique canbe stably performed. When the thickness of the lower molding compound130L is reduced, the entire height of the inter-package connectors 150 amay be reduced. Since the inter-package connectors 150 a are formedusing a soldering process (e.g., a reflow process), when the entireheight of the inter-package connectors 150 a is reduced, the maximumhorizontal width of the inter-package connectors 150 a may be reduced.This is because structures formed using the soldering process may besubstantially spherical. When the maximum horizontal width of theinter-package connectors 150 a is reduced, a volume of the inter-packageconnectors 150 a may be reduced. As such, an interval or pitch betweenthe inter-package connectors 150 a may be reduced. Thus, when thethickness of the lower molding compound 130L is reduced, more numbers ofthe inter-package connectors 150 a may be formed in a given area.According to an embodiment of the inventive concepts, the apparatus 100a having finer and more equally distanced inter-package connectors 150 amay be formed.

The upper semiconductor package 105U may include an upper packagesubstrate 110U and an upper semiconductor chip 115U. The upper packagesubstrate 110U may comprise, for example, a PCB or a ceramic substrate.

The upper semiconductor chip 115U may comprise a memory device, such asa dynamic random access memory (DRAM) device or a flash memory device.The upper semiconductor chip 115U may have a greater horizontal widththan the lower semiconductor chip 115L. When the upper semiconductorchip 115U is wider than the lower semiconductor chip 115L in ahorizontal direction, since an area occupied by the inter-packageconnectors 150 a may be increased, the stack structure 100 a of thesemiconductor packages may be formed to a smaller size. When the areaoccupied by the inter-package connectors 150 a is increased, a largernumber of the inter-package connectors 150 a may be formed.Alternatively, when a same number of the inter-package connectors 150 ais formed, the stack structure 100 a of the semiconductor packages maybe reduced.

The upper semiconductor chip 115U may be disposed on a top surface ofthe upper package substrate 110U. The upper semiconductor chip 115U maybe electrically connected to the upper package substrate 110U throughbonding pads 135, bonding wires 140, and wire pads 145.

The bonding pads 135 may be formed on a top surface of the uppersemiconductor chip 115U. The wire pads 145 may be formed on the topsurface of the upper package substrate 110U. The bonding wires 140 mayelectrically connect the bonding pads 135 with the wire pads 145,respectively.

The upper semiconductor chip 115U may be covered with an upper moldingcompound 130U.

The inter-package connectors 150 a may physically or electricallyconnect the lower semiconductor package 105L with the uppersemiconductor package 105U. The inter-package connectors 150 a mayinclude lower connectors 160 a and upper connectors 180 a, respectively.The lower and upper connectors 160 a and 180 a may include a soldermaterial.

The upper semiconductor chip 115U may have a larger horizontal widththan the lower semiconductor chip 115L. According to an embodiment ofthe inventive concepts, the inter-package connectors 150 a may be formedabove or on a top surface of the lower package substrate 110L where thelower semiconductor chip 115L is formed. The inter-package connectors150 a may be formed below or on a bottom surface of the upper packagesubstrate 110U where the upper semiconductor chip 115U is not formed.Thus, the inter-package connectors 150 a may be affected by the size ofthe lower semiconductor chip 115L. An area standard of the stackstructure 100 a of the semiconductor packages may be determined based onsemiconductor standard rules such as the Joint Electron DeviceEngineering Council (JEDEC) rules. Thus, when the lower semiconductorchip 115L is greater in size than the upper semiconductor chip 115U,restrictions of a space, where the inter-package connectors 150 a may beformed, may be increased with reduced efficiency. According to anembodiment of the inventive concepts, when the upper semiconductor chip115U is greater in size than the lower semiconductor chip 115L, spatialrestrictions may be reduced, and efficiency may be improved. Therefore,according to an embodiment of the inventive concepts, the uppersemiconductor chip 115U may be formed to be greater in size than thelower semiconductor chip 115L. Referring to FIG. 2B, an apparatus 100 bmay include a lower semiconductor package 105L, an upper semiconductorpackage 105U, and inter-package connectors 150 b configured toelectrically connect the lower and upper semiconductor packages 105L and105U. The inter-package connectors 150 b may include lower connectors160 b and upper connectors 180 b. The lower and upper connectors 160 band 180 b may comprise a solder material. The lower connectors 160 b mayhave a hemispherical shape.

Referring to FIG. 2C, an apparatus 100 c may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 c configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 c may include bottom connectors165 c and upper connectors 180 c. Each of the bottom connectors 165 cmay be formed as a mesa or pillar shape. For example, each of the bottomconnectors 165 c may be formed as a circular, cylindrical or polygonalpillar shape.

The bottom connectors 165 c may be attached to a top surface of thelower package substrate 110L. For example, the bottom connectors 165 cmay comprise metal. The bottom connectors 165 c may be formed using, forexample, a casting process, a deposition process, a bonding process, ora plating process.

A metallic barrier layer may be formed on the surfaces of the bottomconnectors 165 c. For example, main bodies of the bottom connectors 165c may comprise copper (Cu), and a nickel (Ni) barrier layer may beformed on the surfaces of the bottom connectors 165 c.

Although it is illustrated that the upper connectors 180 c are greaterin size than the bottom connectors 165 c, the present inventive conceptsis not limited thereto.

The processes of forming the bottom connectors 165 c as a mesa shape onthe top surface of the lower package substrate 110L may be less affectedby a distance between the bottom connectors 165 c than a solderingprocess. Thus, the bottom connectors 165 c may be formed in variousshapes. For instance, each of the bottom connectors 165 c may have asmaller horizontal size and a greater vertical size than the one shownin FIG. 2C. In this case, only small portions of the upper connectors180 c may be formed below the surface of the lower molding compound130L. In other words, the center of the upper connector 180 c may beformed above a top surface of the lower molding compound 130L. Althoughit is illustrated that each of the upper connectors 180 c has an almostcircular sectional shape, the inventive concepts is not limited thereto.For example, each of the upper connectors 180 c may have an ellipticalsectional shape. The upper connectors 180 c may include a soldermaterial.

Referring to FIG. 2D, an apparatus 100 d may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 d configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 d may include lower connectors160 d, intermediate connectors 170 d, and upper connectors 180 d. Eachof the lower connectors 160 d may have a spherical shape or ahemispherical shape. An imaginary center of each of the lower connectors160 d may be formed above or below the top surface of the lower packagesubstrate 110L. The intermediate connectors 170 d may have a mesa shapeand attached to top surfaces of the lower connectors 160 d. Theintermediate connectors 170 d may comprise copper (Cu). A metallicbarrier layer, for example, a nickel (Ni) barrier layer, may be formedon the surfaces of the intermediate connectors 170 d. The lower andupper connectors 160 d and 180 d may comprise a solder material.

Referring to FIG. 2E, an apparatus 100 e may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 e configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 e may include lower connectors160 e, intermediate connectors 170 e, intermediate adhesion parts 175 e,and upper connectors 180 e. The lower connectors 160 e and theintermediate connectors 170 e may be understood with reference to thedescriptions of the lower connectors 160 b and 160 d, the bottomconnectors 165 c, and the intermediate connectors 170 d shown in FIGS.2B through 2D. The intermediate adhesion parts 175 e may be formed onthe intermediate connectors 170 e. Although each of the intermediateadhesion parts 175 e has an elliptical sectional shape, the inventiveconcepts is not limited thereto. For example, each of the intermediateadhesion parts 175 e may have a spherical or hemispherical shape. Inthis case, the shape of the intermediate adhesion parts 175 e may beunderstood with reference to the descriptions of the lower connectors160 b and 160 d shown in FIGS. 2B and 2D. In an embodiment, the centerof the intermediate adhesion parts 175 e may be formed above or belowtop surfaces of the intermediate connectors 170 e. The lower connectors160 e, the intermediate adhesion parts 175 e, and the upper connectors180 e may include a solder material.

Referring to FIG. 2F, an apparatus 100 f may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 f configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 f may include lower connectors160 f and package bumps 190 f. The lower connectors 160 f may beunderstood with reference to FIG. 2A and the description thereof. Eachof the package bumps 190 f may comprise a metal and may have a stud,stick, or pillar shape. The package bumps 190 f may be fabricated usingan additional process and attached or fixed to the upper packagesubstrate 110U. The package bumps 190 f may comprise copper (Cu). Ametallic barrier layer comprising, for example, a nickel (Ni) barrierlayer, may be formed on the surfaces of the package bumps 190 f. Thelower and upper connectors 160 d and 180 d may include a soldermaterial.

Referring to FIG. 2G, an apparatus 100 g may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 g configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 g may include bottom connectors165 g, intermediate adhesion parts 175 g, and package bumps 190 g. Thebottom connectors 165 g, the intermediate connectors 175 g, and thepackage bumps 190 g may be understood with reference to FIGS. 2C through2G and the descriptions thereof.

Referring to FIG. 2H, an apparatus 100 h may include a lowersemiconductor package 105L, an upper semiconductor package 105U, andinter-package connectors 150 h configured to electrically connect thelower and upper semiconductor packages 105L and 105U. The uppersemiconductor package 105U is stacked on the lower semiconductor package105L. The inter-package connectors 150 h may include lower connectors160 h, intermediate connectors 170 h, intermediate adhesion parts 175 h,and package bumps 190 h. The lower connectors 160 h, the intermediateconnectors 170 h, the intermediate adhesion parts 175 h, and the packagebumps 190 h may be understood with reference to FIGS. 2B through 2G andthe descriptions thereof.

FIGS. 3A and 3B are schematic longitudinal sectional views ofapparatuses including chip connectors according to embodiments of theinventive concepts.

Referring to FIG. 3A, an apparatus 200 a may include a lowersemiconductor package 205L including a lower semiconductor chip 215Lhaving chip connectors 281, an upper semiconductor package 205U, andinter-package connectors 250 configured to electrically connect thelower and upper semiconductor packages 205L and 205U. The uppersemiconductor package 205U is stacked on the lower semiconductor package205L. The lower semiconductor package 205L may include a lower moldingcompound 230La, which exposes a top surface of the lower semiconductorchip 215L. The chip connectors 281 may be disposed on the top surface ofthe lower semiconductor chip 215L and physically and/or electricallyconnected to a bottom surface of the upper package substrate 210U. Thechip connectors 281 may electrically connect the lower and uppersemiconductor chips 215L and 215U. The lower semiconductor chip 215L mayinclude through silicon vias (TSVs) 280 formed vertically passingthrough the main body. The TSVs 280 may electrically connect the chipbumps 220 and the chip connectors 281. Although it is illustrated thatthe chip connectors 281 are aligned with the chip bumps 220, the chipconnectors 281 may not be aligned with the chip bumps 220. In anexemplary embodiment, redistribution interconnections may be formed onthe lower semiconductor chip 215L to electrically connect the chip bumps281 and the TSVs 280.

The chip connectors 281 may transmit a clock signal, command signals, anaddress signal, and/or data signals. The inter-package connectors 250may transmit supply voltages, ground voltages, and/or test signals. Inan exemplary embodiment, the chip connectors 281 may transmit the supplyvoltages or ground voltages, and the inter-package connectors 250 maytransmit the effective signals. According to an exemplary embodiment,the chip connectors 281 may transmit the ground voltages, and theinter-package connectors 250 may transmit the supply voltages. Accordingto an exemplary embodiment, when the lower semiconductor chip 215L is alogic device and the upper semiconductor chip 215U is a memory device,the chip connectors 281 may electrically connect shielding groundinterconnections of the lower semiconductor chip 215L with groundinterconnection lines of the upper semiconductor chip 215U. Theshielding ground interconnections may be disposed between signaltransmission lines in logic devices. The shielding groundinterconnections may prevent or reduce interference of electric signalstransmitted through the signal transmission lines. In an exemplaryembodiment, the ground voltages may be transmitted through theinter-package connectors 250. In an exemplary embodiment, the chipconnectors 281 and the inter-package connectors 250 may performdifferent signal transmission functions.

The chip connectors 281 may comprise a solder material.

Referring to FIG. 3B, an apparatus 200 b may include a lowersemiconductor package 205L including a lower semiconductor chip 215Lhaving chip connectors 281, an upper semiconductor package 205U, andinter-package connectors 250 configured to electrically connect thelower and upper semiconductor packages 205L and 205U. The uppersemiconductor package 205U is stacked on the lower semiconductor package205L. The lower semiconductor package 205L may include a lower moldingcompound 230Lb, which covers a top surface of the lower semiconductorchip 215L. The lower molding compound 230Lb may surround bottom surfacesand/or lateral surfaces of the chip connectors 281. In other words, thelower molding compound 230Lb exposes a portion of the chip connectors281.

FIG. 4 is schematic longitudinal sectional view of an apparatusaccording to an embodiment of the inventive concepts.

Referring to FIG. 4, an apparatus 300 may include a lower semiconductorpackage 305L including a lower package substrate 310L and a lowersemiconductor chip 315L, an upper semiconductor package 305U, andinter-package connectors 350 configured to electrically connect thelower and upper semiconductor packages 305L and 305U. The uppersemiconductor package 305U is stacked on the lower semiconductor package305L. The lower package substrate 310L and the lower semiconductor chip315L may be electrically connected to each other by a bonding wire 340L.Each of the lower and upper semiconductor packages 305L and 305U mayinclude a memory device according to an exemplary embodiment. That is,each of the lower and upper semiconductor chips 315L and 315U may be amemory device. In an exemplary embodiment, each of the inter-packageconnectors 350 may include a lower connector 360 and an upper connector380. That is, each of the inter-package connectors 350 may include astack structure of at least two components. In an exemplary embodiment,the lower connectors 360 may be smaller than the upper connectors 380.In an exemplary embodiment, the boundary (or, the cusp or waist) betweenthe lower connector 360 and the upper connector 380 can be disposedbelow the top surface of the lower semiconductor chip 315L. According toan exemplary embodiment, when the size of the lower connectors 360 isreduced and the size of the upper connectors 380 is increased, thearrangement of the inter-package connectors 350 may be finer such thatthe distance between each inter-package connector 350 is closer.

The apparatus described with reference to FIG. 4 may be applied also tothe various apparatuses 100 b to 100 h, 200 a and 200 b described withreference to FIGS. 2B to 3B. In other words, each of the various packageconnectors 150 a to 150 h, 250, and 250 of FIGS. 2A through 3B mayinclude upper components and lower components, and the lower componentsmay be formed below the top surfaces of the lower semiconductor chips.The upper components may include upper connectors 180 a to 180 e and 280or package bumps 190 f to 190 h. The lower components may selectivelyinclude lower connectors 160 a, 160 b, 160 d to 160 f, 160 h, and 260,bottom connectors 165 c and 165 g, intermediate connectors 170 d to 170e and 170 h, and/or intermediate adhesion parts 175 e and 175 g, and 175h. In an embodiment, when the greatest height of the lower components islower than a height of the top surface of the lower semiconductor chip315L, the greatest height of the upper components may be increased. Asthe height of the upper components increases, a process of forming theapparatuses 100 b to 100 h, 200 a, and 200 b of the semiconductorpackages may be stabilized.

FIGS. 5A through 5D are schematic longitudinal sectional views of chipconnectors and connection structures thereof according to embodiments ofthe inventive concepts. FIGS. 5A through 5D illustrate that the chipconnectors are formed between lower semiconductor chips and upperpackage substrates, and top surfaces of the lower semiconductor chipsare exposed.

Referring to FIG. 5A, chip connectors 281 may comprise a singlespherical body between a lower semiconductor chip 215L and an upperpackage substrate 210U. The chip connectors 281 may comprise a soldermaterial. According to an exemplary embodiment, a lateral surface of thelower semiconductor chip 215L may be surrounded by a molding compound230, and a top surface of the lower semiconductor chip 215L may beexposed. The chip connectors 281 may be electrically connected to TSVs280. The chip connectors 281 may be electrically connected to the TSVs280 by redistribution interconnections 279. From a plan view, theredistribution interconnections 279 may have, for example, a pad, bar,or line shape. The pads may electrically connect at least two chipconnectors 281 or TSVs 280. The chip connectors 281, the redistributioninterconnections 279, and/or the TSVs 280 of FIG. 5A may be applied toapparatuses 100 a to 100 h of FIGS. 2A through 2H. That is, apparatuses100 a to 100 h may further include the chip connectors 281, theredistribution interconnections 279, and/or the TSVs 280.

Referring to FIG. 5B, chip connectors 282 including lower chipconnectors 283 and upper chip connectors 284 may be formed between thelower semiconductor chip 215L and the upper package substrate 210L. Thelower chip connectors 283 and the upper chip connectors 284 may includea solder material. The lower chip connectors 283 may be understood withreference to the lower connectors 160 a, 160 b, 160 d, 160 e, 160 f, and160 h shown in FIGS. 2A, 2B, 2D, 2F, and 2H. The upper chip connectors284 may be understood with reference to the upper connectors 180 a to180 e of FIGS. 2A through 2E. In an exemplary embodiment, redistributioninterconnections 279 and TSVs 280 may be formed.

Referring to FIG. 5C, chip connectors 285 including bottom chipconnectors 286 and upper chip connectors 284 may be formed between thelower semiconductor chip 215L and the upper package substrate 210U. Thebottom chip connectors 286 may be formed as a mesa or pillar shape. Thebottom chip connectors 286 may be attached to one surface of the lowersemiconductor chip 215L. The bottom chip connectors 286 may comprisemetal. The bottom chip connectors 286 may be understood with referenceto the bottom connectors 165 c, 165 d, 165 e, 165 g, and 165 h shown inFIGS. 2C, 2D, 2E, and 2H. The upper chip connectors 284 may beunderstood with reference to the upper connectors 180 a to 180 e ofFIGS. 2A through 2E and FIG. 5B. In an exemplary embodiment,redistribution interconnections 279 and TSVs 280 may be formed.

Referring to FIG. 5D, chip connectors 287 including lower chipconnectors 283 and chip connection bumps 288 may be formed between thelower semiconductor chip 215L and the upper package substrate 210U. Thelower chip connectors 283 may be understood with reference to the lowerconnectors 160 a, 160 b, 160 d, 160 e, 160 f, and 160 h of FIGS. 2A, 2B,2D, 2E, 2F, and 2H and FIG. 5B. The chip connection bumps 288 maycomprise, for example, metal. The chip connection bumps 288 may have astud, stick, or pillar shape. The chip connection bumps 288 may befabricated using an additional process and fixed to the upper packagesubstrate 210U. The chip connection bumps 288 may be understood withreference to the package bumps 190 f, 190 g, and 190 h of FIGS. 2F, 2G,and 2H. In an exemplary embodiment, redistribution liens 279 and TSVs280 may be formed.

FIGS. 6A through 6D are schematic longitudinal sectional views of chipconnectors and connection structures thereof according to embodiments ofthe inventive concepts. FIGS. 6A through 6D illustrate that the chipconnectors are formed between lower semiconductor chips and upperpackage substrates, and top surfaces of the lower semiconductor chipsare partially or wholly covered with a lower molding compound. Variouschip connectors that will now be illustrated and described may havesimilar structural shapes as the inter-package connectors 150 a to 150 hof FIGS. 2A through 2H and/or the chip connectors 281, 282, 285, and 287of FIGS. 5A through 5D. According to exemplary embodiments, the sizes ofthe chip connectors may be variously determined according to designrules.

Referring to FIGS. 6A through 6D, the lower molding compound 230La maycover a top surface of the lower semiconductor chip 215L. Thus, bottomand lateral surfaces of the chip connectors 281, 282, 285, and 287 maybe partially or wholly surrounded by the lower molding compound 230La.In an exemplary embodiment, the bottom and/or lateral surfaces of thechip connectors 281, 282, 285, and 287 may be partially exposed from thelower molding compound 230La. According to an exemplary embodiment,redistribution interconnections 279 and TSVs 280 may be formed.

FIGS. 7A through 7D are schematic longitudinal sectional views ofvarious inter-package connectors according to embodiments of theinventive concepts. The substantially round or circular shapes areshapes of various inter-package connectors and/or chip connectors beforea reflow process is performed.

The various connectors may refer to any one or portion of the variousinter-package connectors and chip connectors shown in FIGS. 1A through6D.

Referring to FIG. 7A, a connector 50 a may include a lower connector 60a and an upper connector 80 a. In an exemplary embodiment, the upperconnector 80 a may have a greater volume than the lower connector 60 a.In an exemplary embodiment, a vertical height H1 of the upper connector80 a may be greater than a vertical height H2 of the lower connector 60a. In an exemplary embodiment, a horizontal width D1 of the upperconnector 80 a may be greater than a horizontal width D2 of the lowerconnector 60 a. From a plan view or cross-sectional view, the horizontalwidths D1 and D2 may be understood as diameters of the upper connector80 a and the lower connector 60 a, respectively. In an exemplaryembodiment, a radius or curvature r1 of the upper connector 80 a may begreater than a radius or curvature r2 of the lower connector 60 a. Thelower connector 60 a and the upper connector 80 a may include a soldermaterial. Thus, the lower connector 60 a and the upper connector 80 amay be formed using a soldering process, and the upper and lowerconnectors 80 a and 60 a may have a spherical or hemispherical shape.

Referring to FIG. 7B, a connector 50 b may include a lower connector 60b and an upper connector 80 b, and the upper connector 80 b may have agreater volume than the lower connector 60 b. An imaginary center C1 ofthe lower connector 60 b may be disposed at the same level as a bottomsurface 10. The imaginary center C1 may be interpreted as the center ofan imaginary radius or curvature r3 of the lower connector 60 b. Thelower connector 60 b and the upper connector 80 b may include a soldermaterial. In an exemplary embodiment, the lower connector 60 b may havea hemispherical shape.

Referring to FIG. 7C, a connector 50 c may include a lower connector 60c and an upper connector 80 c. In an exemplary embodiment, the upperconnector 80 c may have a greater volume than the lower connector 60 c.An imaginary center C2 of the lower connector 60 c may be at a lowerlevel than a bottom surface 10. The imaginary center C2 may beinterpreted as the center of an imaginary radius or curvature r4 of thelower connector 60 c.

Referring to FIG. 7D, a connector 50 d may include a lower connector 60d and an upper connector 80 d, and the upper connector 80 d may have agreater volume than the lower connector 60 d. An imaginary center C3 ofthe lower connector 60 d may be at a higher level than the bottomsurface 10. The imaginary center C3 may be interpreted as the center ofan imaginary radius or curvature r5 of the lower connector 60 d.

According to embodiments of the inventive concepts, the upper connectors80 a to 80 d may be formed to be higher, wider, and larger than thelower connectors 60 a to 60 d. The lower connectors 60 a to 60 d may beformed using a screen print process or soldering process according to anexemplary embodiment. The upper connectors 80 a and 80 b may be formedusing a soldering process according to an exemplary embodiment.According to an exemplary embodiment, a process of connecting the upperconnectors 80 a to 80 d and the lower connectors 60 a to 60 d may beperformed within a via hole formed using a laser drilling process. Theformation of the via hole may include selectively removing a moldingcompound to partially expose surfaces of the lower connectors 60 a to 60d. The laser drilling process may enable to form finer and more equaldistanced via holes than the screen print process. Therefore, a laserdrilling process may be performed to enable elaborate arrangement of theconnectors 50 a. As the size of the lower connectors 60 a to 60 ddecreases, the screen print process may not contribute towardelaborately arranging the lower connectors 60 a to 60 d, and as the sizeof the upper connectors 80 a to 80 d increases, the laser drillingprocess may contribute toward elaborately arranging the upper connectors80 a to 80 d. Thus, the upper connectors 80 a to 80 d may have a greatersize than the lower connectors 60 a to 60 d to make the connectors 50 ato 50 d more elaborate. For example, the connectors can be formed withsubstantially equal distances between them. For example, more numbers ofconnectors can be formed in a given area. In an exemplary embodiment,before performing a reflow process to connect the lower connectors 60 ato 60 d with the upper connectors 80 a to 80 d, respectively, the upperconnectors 80 a to 80 d may be dipped in a flux. A sufficient amount offlux may be applied to the surfaces of the upper connectors 80 a to 80 dso that the reflow process can be stably carried out. In other words, asthe size of the upper connectors 80 a to 80 d increases, a larger amountof flux may be applied to the surfaces of the upper connectors 80 a to80 d. Accordingly, the upper connectors 80 a to 80 d may be formed tothe greatest possible size while minimizing a distance between the upperconnectors 80 a to 80 d. In general, the upper package substrate 110Umay be uneven. During a semiconductor package fabrication process, theupper package substrate 110U may not maintain flatness. That is, theupper package substrate 110U may be bent. Thus, when the upperconnectors 80 a to 80 d are not formed to have a sufficiently largesize, a sufficient amount of flux may not be applied to the surfaces ofthe upper connectors 80 a to 80 d. Accordingly, the upper connectors 80a to 80 d are formed to have a greater size than the lower connectors 60a to 60 d according to exemplary embodiments of the inventive concepts.

FIGS. 8A through 8I are shapes of various connectors of package stackstructures according to embodiments of the inventive concepts. Here, theshapes may be interpreted as finally formed shapes of respectivecomponents. The various connectors may refer to any one or portion ofthe various inter-package connectors and chip connectors shown in FIGS.1A through 6D. Generally, these shapes of the connectors are generatedafter a reflow process. The reflow process can be used when a lowerconnector is formed on a substrate. The reflow process can be used whenan upper connector is formed on a substrate. The reflow process can beused when the lower connector and the upper connector are combined.

Referring to FIG. 8A, a connector 51 a may include a waist portion Waand be formed to physically and/or electrically connect a lower land 12a and an upper land 17 a. The waist portion Wa refers to a slenderportion of the connector 51 a. The waist portion Wa may imaginarilyand/or visually divide the connector 51 a into an upper part and a lowerpart. In other words, the waist portion Wa may divide the connector 51 ainto an upper connector 81 a and a lower connector 61 a. The maximumwidth Da1 of the upper connector 81 a may be more than the maximum widthDa2 of the lower connector 61 a. A width Da3 of the waist portion Wa maybe less than the maximum width Da2 of the lower connector 61 a. Thus,the waist portion Wa refers to a portion having a smallest width Da3,which is interposed between the maximum width Da2 of the lower connector61 a and the maximum width Da1 of the upper connector 81 a. A height Ha1of the upper connector 81 a may be defined as a distance between thesurface of the upper land 17 a or an upper insulating material 18 a,which partially covers the upper land 17 a, and the waist portion Wa. Aheight Ha2 of the lower connector 61 a may be defined as a distancebetween the surface of the lower land 12 a or a lower insulatingmaterial 13 a, which partially covers the lower land 12 a, and the waistportion Wa. The height Ha1 of the upper connector 81 a may be greaterthan a height Ha2 of the lower connector 61 a. In an embodiment, theupper connector 81 a may have a greater volume than the lower connector61 a. In an embodiment, the maximum width Da1 of the upper connector 81a may be disposed above the middle of the upper connector 81 a. Thewaist portion Wa may be formed in the horizontal direction. The upperand lower connectors 81 a and 61 a may include a solder material. Theupper and lower connectors 81 a and 61 a may have a spherical orhemispherical shape. Thus, from a plan or cross-sectional view, thehorizontal widths Da1, Da2, and Da3 may refer to diameters of circles.

Referring to FIG. 8B, a connector 51 b may include a waist portion Wb bywhich an upper connector 81 b is divided from a lower connector 61 b,and an imaginary center C of the lower connector 61 b may be disposed ata lower level than the surface of the lower land 61 b. A case where theimaginary center C of the lower connector 61 b may be disposed at ahigher level than the surface of the lower land 61 b may be understoodwith reference to FIG. 8A. The maximum width Db1 of the upper connector81 b may be greater than a width Db2 of the waist portion Wb. A heightHb1 of the upper connector 81 b may be greater than a height of thelower connector 61 b.

Referring to FIG. 8C, a connector 51 c may include a mesa shape bottomconnector 61 c and a spherical upper connector 81 c, and a height Hc1 ofthe upper connector 81 c may be greater than a height Hc2 of the bottomconnector 61 c. The maximum width Dc1 of the upper connector 81 c may begreater than a width Dc2 of the bottom connector 61 c. A portion of thetop surface of the mesa shape bottom connector 61 c may not contact theupper connector 81 c. That is, the mesa shape bottom connector 61 c maybe exposed.

Referring to FIG. 8D, a connector 51 d may include a spherical orhemispherical lower connector 61 d, a mesa shape intermediate connector71 d, and a spherical upper connector 81 d. A height Hd1 of the upperconnector 81 d may be greater than a height Hd2 of the intermediateconnector 71 d or a height Hd3 of the lower connector 61 d. In anembodiment, the height He1 of the upper connector 81 d may be greaterthan the sum (Hd2+Hd3) of the height Hd2 of the intermediate connector71 d and the height Hd3 of the lower connector 61 d. The maximum widthDd1 of the upper connector 81 d may be greater than a width Dd2 of thebottom connector 66 d. A portion of the top surface of the intermediateconnector 71 d may not contact the upper connector 81 d. That is, theportion of the top surface of the intermediate connector 71 d can beexposed. A lower portion of a lateral surface of the intermediateconnector 71 d may be partially covered with the lower connector 61 d.

Referring to FIG. 8E, a connector 51 e may include a lower connector 61e, an intermediate connector 71 e, an intermediate adhesion unit 76 e,and an upper connector 81 e. The upper connector 81 e and theintermediate adhesion unit 76 e may be visually distinguished from eachother on the basis of a waist portion We. The maximum width of the upperconnector 81 e may be greater than the maximum width De2 of theintermediate adhesion unit 76 e. The greatest width of the intermediateadhesion unit 76 e may be greater than the width of the waist portionWe. The heights of respective components may be variously determined.For example, although it is illustrated that the upper connector 81 ehas a greatest height, the inventive concepts is not limited thereto.When the connector 51 e has a multilayered structure, the relativeheights, widths, or sizes of respective components may be variouslyapplied.

Referring to FIG. 8F, a connector 51 f may include a lower connector 61f and a bump portion 81 f. The bump portion 81 f may comprise a metalhaving a stud or pillar shape. A height Hf1 of the bump portion 81 f maybe greater than a height Hf2 of the lower connector 61 f. A lowerportion of a lateral surface of the bump portion 81 f may be coveredwith the lower connector 61 f. The lower connector 61 f may be formed asa spherical or hemispherical shape. An imaginary center of the lowerconnector 61 f may be disposed above or below the surface of the lowerland 12 f.

Referring to FIG. 8G, a connector 51 g may include a bottom connector 66g, an intermediate adhesion unit 76 g, and a bump portion 91 g. A heightHg1 of the bump portion 91 g may be greater than a height Hg2 of theintermediate adhesion unit 76 g or a height Hg3 of the bottom connector66 g.

Referring to FIG. 8H, a connector 51 h may include a lower connector 61h, an intermediate connector 71 h, an intermediate adhesion unit 76 h,and a bump portion 91 h. A height Hh1 of the bump portion 91 h may begreater than a height Hh2 of the intermediate adhesion unit 76 h, aheight Hh3 of the intermediate connector 71 h, or a height Hh4 of thelower connector 61 h.

Referring to FIG. 8I, a connector 51 i may include a waist portion Wi bywhich an upper connector 81 i is divided from a lower connector 61 i,and the lower connector 61 i may include sidewalls having planarportions SWi. The planar portions SWi may correspond to portions ofsidewalls of the lower connector 61 i. The planar portions SWi mayextend to a bottom portion of the lower connector 61 i.

The upper lands 17 a to 17 i of FIGS. 8A through 8I may be included inthe upper packages 105U and 205U of FIGS. 2A through 2H, 3A, and/or 3B,and the lower lands 12 a to 12 h may be included in the lower packages105L and 205L or the lower semiconductor chips 115L and 215L.

FIGS. 9A through 9I are shapes of various connectors and via holes in anapparatus according to embodiments of the inventive concepts.

Referring to FIG. 9A, a connector 52 a may include a lower connector 62a and an upper connector 82 a, and the upper connector 82 a may beformed within a via hole Va configured to partially expose the surfaceof the lower connector 62 a. A width Dva of a bottom end Vla of the viahole Va may be smaller than the maximum width Dla of the lower connector62 a. A gap Ga may be formed between the via hole Va and the waistportion Wa.

Referring to FIG. 9B, a connector 52 b may include a lower connector 62b and an upper connector 82 b, and the upper connector 82 b may beformed within a via hole Vb configured to substantially or completelyexpose the surface of the lower connector 62 b. The lower connector 62 bmay include sidewalls having planar portions SWb. A width Dvb of abottom end of the via hole Vb may be greater than a width Dlb of abottom end of the lower connector 62 b. Thus, a gap Gb1 may be formedbetween the via hole Vb and a bottom portion of the lower connector 62b.

Referring to FIG. 9C, a connector 52 c may include a lower connector 62c and an upper connector 82 c, and the upper connector 82 c may beformed within a via hole Vc configured to substantially or completelyexpose the surface of the lower connector 62 c. The lower connector 62 cmay include sidewalls having planar portions SWc. The planar portionsSWc may extend to a bottom surface 23 c.

Gaps Ga, Gb, and Gc may be formed between the waist portions Wa, Wb, andWe of the connectors 52 a, 52 b, and 52 c shown in FIGS. 9A through 9Cand sidewalls of the via holes Va, Vb, and Vc. The sidewalls of the viaholes Va, Vb, and Vc may be inclined such that the diameters of the viaholes Va, Vb, and Vc may be reduced toward lower portions thereof. Thesidewalls of the via holes Va, Vb, and Vc may be inclined atrespectively different angles. For example, each of the inclinationsidewalls of the via holes Va, Vb, and Vc may be determined at an angleof about 10° to about 30° in consideration of intervals or pitchesbetween the via holes Va, Vb, and Vc and other adjacent connectors. Thevia holes Va, Vb, and Vc may vertically penetrate molding compounds 32a, 32 b, and 32 c and partially expose top and/or lateral surfaces ofthe lower connectors 62 a, 62 b, and 62 c or the surfaces of lowerinsulating materials 23 a, 23 b, and 23 c.

Referring to FIG. 9D, a connector 52 d may include a lower connector 62d, a mesa shape connector 67 d and an upper connector 82 d, and theupper connector 82 d may be formed within a via hole Vd configured topartially expose the surface of the mesa shape connector 67 d. A widthDvd of a bottom end of the via hole Vd may be greater than a horizontalwidth Dmd of the mesa shape connector 67 d. A gap Gd may be formed on aportion of the surface of the mesa shape connector 67 d.

Referring to FIG. 9E, a connector 52 e may include a lower connector 62e, a mesa shape connector 67 e and an upper connector 82 e, and theupper connector 82 e may be formed within a via hole Ve configured topartially expose a lateral surface of the mesa shape connector 67 e. Awidth Dve of a bottom end of the via hole Ve may be equal to ahorizontal width of the mesa shape connector 67 e. A gap Ge may beformed between a portion of the lateral surface of the mesa shapeconnector 67 e and the sidewall of the via hole Ve.

Referring to FIG. 9F, an upper connector 82 f may include a lowerconnector 62 f, a mesa shape connector 67 f and an upper connector 82 f,and the upper connector 82 f may be formed within a via hole Vfconfigured to wholly expose a lateral surface of the mesa shapeconnector 67 f. The via hole Vf may partially expose a top surface ofthe lower connector 62 f. A gap Gf may be formed between a portion ofthe lateral surface of the mesa shape connector 67 f and a sidewall ofthe via hole Vf.

According to an embodiment, in FIGS. 9D through 9F, sidewalls of the viaholes Vd, Ve, and Vf may be inclined such that the diameters of the viaholes Vd, Ve, and Vf may be reduced toward lower portions thereof. Thevia holes Vd, Ve, and Vf may vertically penetrate molding compounds 32d, 32 e, and 32 f and partially or wholly expose top and/or lateralsurfaces of the mesa shape connectors 67 d, 67 e, and 67 f.

Referring to FIG. 9G, a connector 52 g may include a lower connector 62g, a mesa shape connector 67 g, an intermediate connector 77 g, and anupper connector 82 g. The upper connector 82 g may be formed within avia hole Vg configured to partially expose the surface of theintermediate connector 77 g. A gap Gg may be formed between a portion ofthe surface of the intermediate connector 77 g and a sidewall of the viahole Vg.

Referring to FIG. 9H, a connector 52 h may include a lower connector 62h, a mesa shape connector 67 h, an intermediate connector 77 h, and anupper connector 82 h. The upper connector 82 h may be formed within avia hole Vh configured to partially expose the surface of the mesa shapeconnector 67 h. The via hole Vh may further expose a portion of thelateral surface of the mesa shape connector 67 h. A gap Gh may be formedbetween the portion of the surface of the mesa shape connector 67 h anda sidewall of the via hole Vh.

Referring to FIG. 9I, a connector 52 i may include a lower connector 62i, a mesa shape connector 67 i, an intermediate connector 77 i, and anupper connector 82 i. The upper connector 82 i may be formed within avia hole Vi configured to partially expose the surface of the lowerconnector 62 i. A gap Gi may be formed between the portion of thesurface of the lower connector 62 i and a sidewall of the via hole Vi.

According to an embodiment, in FIGS. 9G through 9I, sidewalls of the viaholes Vg, Vh, and Vi may be inclined such that the diameters of the viaholes Vg, Vh, and Vi may be reduced toward lower portions thereof. Thevia holes Vg, Vh, and Vi may vertically penetrate molding compounds 32g, 32 h, and 32 i and partially or wholly expose the surface of theintermediate connector 77 h, partially or wholly expose the surface ofthe mesa shape connector 67 h, and partially or wholly expose thesurface of the lower connector 62 h. The gaps Gb1 and Ga to Gi may referto air gaps.

FIGS. 10A through 10F are schematic longitudinal sectional viewsillustrating a process of forming an upper package according to anembodiment of the inventive concepts.

Referring to FIG. 10A, an upper package substrate 110U including upperlands 155U and wire pads 145 may be prepared. The upper lands 155U maybe electrically connected to the wire pads 145, respectively. The upperlands 155U and the wire pads 145 may be formed using, for example, ascreen printing process, a deposition process, a bonding process, or aplating process.

Referring to FIG. 10B, upper semiconductor chips 115U may be mounted onthe upper package substrate 110U. An insulating adhesive may beinterposed between the upper package substrate 110U and the uppersemiconductor chips 115U. The upper semiconductor chips 115U may includebonding pads 135.

Referring to FIG. 10C, the bonding pads 135 may be electricallyconnected to the wire pads 145 using bonding wires 140.

Referring to FIG. 10D, an upper molding compound 130U may be formed tocover the upper semiconductor chips 115U and separated into the uppersemiconductor chips 115U. The upper molding compound 130U may comprisean epoxy resin or polyimide. The separation of the upper moldingcompound 130U may be performed using, for example, a sawing process or acutting process.

Referring to FIG. 10E, the upper semiconductor package 105U may beturned upside down, and upper connectors 180 may be formed on the upperlands 155U, respectively.

According to exemplary embodiments of the inventive concepts, referringto FIG. 10F, package bumps 190 may be formed on the upper lands 155U,respectively.

FIGS. 11A through 11I show a method of fabricating an apparatusaccording to embodiments of the inventive concepts.

Referring to FIG. 11A, lower lands 155L may be formed on a lower packagesubstrate 110L. The lower lands 155L may be formed using a screenprinting technique. Alternatively, the lower lands 155L may be formedusing a deposition technique, a bonding technique, a plating technique,or an inkjet technique. In an embodiment, chip bump lands 121 may beformed using the same process as or a different process from the processof forming the lower lands 155L. That is, the lower lands 155L and thechip bump lands 121 may be formed on the lower package substrate 110L.

Referring to FIG. 11B, conductive chip bumps 120 may be formed on thelower package substrate 110L. The conductive chip bumps 120 may beformed using a screen printing process, an inkjet process, or asoldering process. The conductive chip bumps 120 may be electricallyconnected to the chip bump lands 121, respectively.

Referring to FIG. 11C, lower connectors 160 may be formed on the lowerlands 155L. The lower connectors 160 may be formed using, for example, ascreen printing technique, an inkjet technique, or a solderingtechnique. The lower connectors 160 may be formed during the formationof the conductive chip bumps 120. In other words, the conductive chipbumps 120 and the lower connectors 160 may be formed simultaneously.Although FIG. 11C illustrates that the lower connectors 160 may beformed at about the same level with the conductive chip bumps 120, thepresent inventive concepts is not limited thereto. The lower connectors160 may be formed at a sufficiently higher level than the conductivechip bumps 120. When the conductive chip bumps 120 and the lowerconnectors 160 are at the same level, the conductive chip bumps 120 andthe lower connectors 160 are formed simultaneously. Also, when theconductive chip bumps 120 and the lower connectors 160 are at differentlevels, the conductive chip bumps 120 and the lower connectors 160 areformed using different processes.

Referring to FIG. 11D, lower semiconductor chips 115L may be mounted onthe conductive chip bumps 120. The lower semiconductor chips 115L may beformed as a flip chip shape and may be logic devices. The lowerconnectors 160 may be formed before mounting the lower semiconductorchips 115L. For example, when the lower connectors 160 are formed usinga screen printing technique, the lower connectors 160 may be formedbefore mounting the lower semiconductor chips 115L. However, when thelower connectors 160 are formed using a soldering technique, theformation of the lower connectors 160 may be formed after mounting thelower semiconductor chips 115L.

Referring to FIG. 11E, a molding control film 135 may be formed on thelower semiconductor chips 115L. The molding control film 135 may beclosely adhered to top surfaces of the lower semiconductor chips 115L. Aspace may be ensured between the molding control film 135 and the lowerpackage substrate 110L. A space may be ensured between the moldingcontrol film 135 and the surfaces of the lower connectors 160. Themolding control film 135 may be a tape comprising, for example,cellulose, acetate, polyvinyl, or polyurethane.

Referring to FIG. 11F, the space between the molding control film 135and the lower package substrate 110L may be filled with a lower moldingcompound 130L. The lower molding compound 130L may be formed to coverthe lower connectors 160, surround a lateral surface of the lowersemiconductor chip 115L, and fill a lower region of the molding controlfilm 135. The lower molding compound 130L may be formed only around theconductive chip bumps 120. In other words, the lower molding compound130L may only fill spaces between the lower package substrate 110L andthe lower semiconductor chips 115L. That is, lateral surfaces of thelower semiconductor chips 115L may be exposed to the air. In anembodiment, the lower molding compound 130L may be an insulatingadhesive. Alternatively, lower lateral surfaces of the lowersemiconductor chips 115L may be surrounded by the lower molding compound130L, while upper lateral surfaces thereof may be exposed to the air. Inan embodiment, the lower molding compound 130L may cover the surfaces ofthe lower connectors 160. In other words, the lower molding compound130L may fill half the space between the molding control film 135 andthe lower package substrate 110L.

Referring to FIG. 11G, the molding control film may be removed, and alaser drilling process may be performed to expose the surface of thelower connectors 160. During the laser drilling process, the lowermolding compound 130L may be selectively removed, and openings O may beformed to partially or wholly expose the surfaces of the lowerconnectors 160. A distance between top surfaces of the lower connectors160 and a top surface of the molding compound 130L may be greater than adistance between the surface of the lower package substrate 110L and topsurfaces of the lower connectors 160. Alternatively, spaces of theopenings O may be greater than volumes of the lower connectors 160. Whenregarding the openings O as via holes, inner spaces of the via holes maybe greater than the volumes of the lower connectors 160. In anembodiment, the spaces of the openings O or the inner spaces of the viaholes may be greater than the volumes of the lower connectors 160 interms of any one of a vertical length, a horizontal maximum width, and amaximum diameter.

Referring to FIG. 11H, solder balls 125 may be formed on a bottomsurface of the lower package substrate 110L. The solder balls 125 may beelectrically connected to the conductive chip bumps 120, respectively.The solder balls 125 may be formed using a soldering process. Accordingto embodiments of the inventive concepts, the process of forming thesolder balls 125 may be performed before the laser drilling process.

Referring to FIG. 11I, the lower package substrate 110L and the lowermolding compound 130L may be separated into single lower semiconductorpackages 105L. The separation process may be performed using, forexample, a sawing process, a drilling process, or a cutting process.

Referring to FIG. 11J, the upper connectors 180 of the uppersemiconductor package 105U of FIG. 10E may be dipped in a solder flux Fcontained in a container T. In an embodiment, a top surface of thecontainer T may be in contact with or close to the surface of the upperpackage substrate 110U. The top surface of the container T may functionto determine the depth of the solder flux F in which the upperconnectors 180 are dipped. In an embodiment, when the upper connectors180 have a sufficiently large size, the upper connectors 180 may besufficiently dipped in the solder flux F. As the size of the upperconnections 180 increases, the surface areas of the upper connections180 dipped in the solder flux F also increase. As such, physical orelectrical connection between the upper connectors 180 and the lowerconnectors 160 can be improved. The size or surface area of the upperconnector 180 may refer to a height of the upper connectors 180 formedon the surface of the upper package substrate 110U. According to anembodiment of the inventive concepts, the upper connectors 180 may beformed to a greater size or surface area than the lower connectors 160.According to an embodiment, a connection structure that is more stablein physical and electrical aspects is provided. The upper packagesubstrate 110U may have a slightly or substantially twisted or bentshape. The upper package substrate 110U may be bent during thefabrication. When the upper connectors 180 are not formed to have asufficiently large size, some of the upper connectors 180 may not bedipped in the solder flux F, or the surface of the upper packagesubstrate 110U may contact the solder flux F. As such, the surface ofthe upper package substrate 110U can be stained. Therefore, when theupper connectors 180 are formed to have a sufficiently large sizeaccording to an embodiment of the inventive concepts, unstable factorsdue to the warpage of the upper package substrate 110U may besufficiently removed.

Referring to FIG. 11K, the upper semiconductor package 105U and thelower semiconductor package 105L may be stacked. The surfaces of theupper connectors 180 are sufficiently stained with the fluid F. In anembodiment, the lower connectors 160 and the upper connectors 180 may beheated and bonded to each other under pressure in the openings O andphysically and electrically combined and/or connected with each other.Here, combining the lower and upper connectors 160 and 180 may beinterpreted as integrally forming the lower and upper connectors 160 and180.

Referring to FIG. 11L, the package bumps 190 of the upper semiconductorpackage 105U of FIG. 10F may be dipped in the solder flux F. Subsequentprocesses may be understood with reference to FIG. 11K.

During the soldering process, a solder material may have a sphericalshape due to surface tension. Thus, when a component is described orillustrated as a spherical or hemispherical shape, the component may beformed using a soldering process. It will be understood by those skilledin the art with reference to the above drawings and the descriptionsthereof that the lower and upper connectors 160 and 180 may be formed invarious shapes.

FIGS. 12A and 12B are schematic diagrams of semiconductor modulesincluding apparatuses formed according to embodiments of the inventiveconcepts.

Referring to FIGS. 12A and 12B, each of semiconductor modules 500 a and500 b may include a module board 510 a or 510 b and a plurality ofsemiconductor devices 520 mounted on the module board 510 a or 510 b. Atleast one of the plurality of semiconductor devices 520 may includeapparatuses according to embodiments of the inventive concepts. Each ofthe module boards 510 a and 510 b may be a PCB. The semiconductor module500 a or 500 b may include a plurality of contact terminals 530 formedin a lateral surface of the module board 510 a or 510 b. Each of thecontact terminals 530 may be electrically connected to the semiconductordevices 520.

FIG. 13 is a schematic diagram of an electronic system including anapparatus according to embodiments of the inventive concepts.

Referring to FIG. 13, an electronic system 600 may include a controlunit 610, an input unit 620, an output unit 630, a storage unit 640, anda communication unit 650 according to an exemplary embodiment.

The control unit 610 may control the electronic system 600 andrespective components at one time. The control unit 610 may be a centralprocessing unit (CPU) or a main control unit (MCU) and include thesemiconductor module 500 according to embodiments of the inventiveconcepts. The control unit 610 may include a stack structure ofsemiconductor packages according to embodiments of the inventiveconcepts.

The input unit 620 may transmit an electrical command signal to thecontrol unit 610. The input unit 620 may comprise, for example, akeyboard, a keypad, a mouse, a touch pad, an image recognizer such as ascanner, or one of various input sensors. The input unit 620 may includea stack structure of semiconductor packages according to embodiments ofthe inventive concepts.

The output unit 630 may receive the electrical command signal from thecontrol unit 610 and output a processing result of the electronic system600. The output unit 630 may comprise, for example, a monitor, aprinter, or a beam emitter. The output unit 630 may include a stackstructure of semiconductor packages according to embodiments of theinventive concepts.

The storage unit 640 may be a component configured to temporarily orpermanently store an electrical signal to be processed or alreadyprocessed by the control unit 610. The storage unit 640 may bephysically and electrically connected to or combined with the controlunit 610. The storage unit 640 may comprise, for example, asemiconductor memory device, a magnetic storage device such as a harddisk, and optical storage device such as a compact disk, or a serverhaving a data storage function. The storage unit 640 may include a stackstructure of semiconductor packages according to embodiments of theinventive concepts.

The communication unit 650 may receive an electrical command signal fromthe control unit 610 and transmit or receive the electrical signal to orfrom another electronic system. The communication unit 650 may comprise,for example, a wired transceiving device such as a modem or a local areanetwork (LAN) card, a wireless transceiving device such as a wirelessbroadband (WiBro) interface, or an infrared (IR) port. The communicationunit 650 may include a stack structure of semiconductor packagesaccording to embodiments of the inventive concepts.

The electronic system 600 according to embodiments of the inventiveconcepts may comprise, for example, a computer, a network server, anetworking printer, a scanner, a wireless controller, a mobilecommunication terminal, a switching system, or any electronic devicecapable of programmed operations.

According to embodiments of the inventive concepts as described above, astack structure of semiconductor packages may include inter-packageconnectors stably formed even when a distance between the inter-packageconnectors is substantially small.

Although the exemplary embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the present invention should not be limited to thoseprecise embodiments and that various other changes and modifications maybe affected therein by one of ordinary skill in the related art withoutdeparting from the scope or spirit of the invention. All such changesand modifications are intended to be included within the scope of theinvention as defined by the appended claims.

1. (canceled)
 2. A method for fabricating a semiconductor package,comprising: mounting a first semiconductor chip on a first area of afirst substrate; disposing a first connector on a second area of thefirst substrate; placing a first molding compound on the first substratesuch that the first molding compound contacts side surfaces of the firstsemiconductor chip and covers the first connector and a top surface ofthe first semiconductor chip is not covered with the first moldingcompound; forming an opening through the first molding compound toexpose a portion of the first connector; disposing a second connectorand a second semiconductor chip on lower surface and upper surface of asecond substrate, respectively; and placing the second substrate on thefirst substrate such that the second connector contacts the firstconnector.
 3. The method of claim 2, the opening through the firstmolding compound is formed by a laser drilling process.
 4. The method ofclaim 3, wherein each of the first and second connectors is a solderball.
 5. The method of claim 4, the second connector has a larger volumethan that of the first connector.
 6. The method of claim 4, the secondconnector has a larger radius than that of the first connector.
 7. Themethod of claim 4, the first connector is configured to prevent theopening from extending into the first substrate during the laserdrilling process.
 8. The method of claim 2, wherein the first moldingcompound surrounds at least a portion of the second connector.
 9. Themethod of claim 2, wherein a plurality of conductive chip bumps aredisposed between the first semiconductor chip and the first substratesuch that connecting the first semiconductor chip is electricallyconnected with the first substrate.
 10. The method of claim 9, whereinthe first molding compound fills a gap between the first semiconductorchip and the first substrate.
 11. The method of claim 2, furthercomprising: placing a second molding compound to be in contact with thesecond semiconductor chip.
 12. The method of claim 2, furthercomprising: forming a wire bonding that electrically connects the secondsemiconductor chip with the second substrate.
 13. The method of claim 2,further comprising: placing a molding control film on the firstsemiconductor chip; and horizontally extending the molding control filmover the first substrate before placing the first molding compound suchthat the first molding compound does not cover the top surface of thefirst semiconductor chip; and detaching the molding control film afterthe horizontally extending.
 14. The method of claim 13, wherein a spacebetween the molding control film and the first substrate is filled withthe first molding compound.
 15. The method of claim 14, wherein themolding control film includes one of cellulose, acetate, polyvinyl, orpolyurethane.
 16. A method for fabricating a semiconductor package,comprising: mounting a first semiconductor chip on a first area of afirst substrate; disposing a first connector on a second area of thefirst substrate; placing a molding control film on the firstsemiconductor chip, the molding control film horizontally extending overthe first substrate; filling a space between the molding control filmand the first substrate with a first molding compound such that thefirst molding compound contacts side surfaces of the first semiconductorchip and covers the first connector and a top surface of the firstsemiconductor chip is not covered with the first molding compound;detaching the molding control film; forming an opening through the firstmolding compound to expose a portion of the first connector; disposing asecond connector and a second semiconductor chip on opposite surfaces ofa second substrate, respectively; and placing the second substrate onthe first substrate such that the second connector contacts the firstconnector.
 17. The method of claim 16, the opening through the firstmolding compound is formed by a laser drilling process.
 18. The methodof claim 17, wherein each of the first and second connectors is a solderball.
 19. The method of claim 18, the second connector has a largervolume than that of the first connector.
 20. The method of claim 18, thesecond connector has a larger radius than that of the first connector.21. The method of claim 18, the first connector is configured to preventthe opening from extending into the first substrate during the laserdrilling process.